6 notebooks cost $8.34. Which equation would help determine the cost of 5 notebooks?
There are several equations that could help determine the cost, each with a slightly different approach. We know the cost of 6 notebooks. We want to know the cost of 5 notebooks. We can write the numbers of notebooks as a proportion: $\dfrac{6}{5}$ We know 6 notebooks costs $8.34. We can let $x$ represent the unknown cost of 5 notebooks. The proportion of these costs can be expressed as: $\dfrac{\$8.34}{x}$ The cost changes along with the number of notebooks purchased, and so the two proportions are equivalent. $\dfrac{6}{5} = \dfrac{\$8.34}{x}$